Oil jet nozzles have long been used to cool the under side of a piston in a reciprocating piston engine. These nozzles are often mounted into a bore that leads to an oil gallery. The nozzle also incorporates a check valve to prevent siphoning off of needed oil pressure during low oil pressure conditions.
However, several problems are evident with known oil jet piston cooling systems. Firstly, threaded nozzles tend to eventually twist about in its bore to misalign the nozzle from the intended area at the underside of the piston.
Secondly, the jet nozzle effectively sprays only one-half of the piston underside. The piston rod blocks the spray path to the other side of the piston from where the nozzle is located. It is now common to have asymmetrical engine combustion and consequently the piston heats unevenly with one side ending up hotter than another side. This asymmetry can be caused by chambers that are asymmetrically contoured and precombustion chambers that may have entrances leading into the main combustion chamber at side locations.
The oil spray thus is desirably directed toward the hotter side. No problems exist when the oil gallery is also positioned on the hot side because the jet nozzle may be merely tapped into the oil gallery and pointed directly upwardly to the hot side with no obstruction therebetween. However, in engines designed with the hotter side on an opposite side relative to the oil gallery, problems arise as to how to provide a nozzle that can both have access to the oil supply while simultaneously directing oil spray without intervening obstructions to the hot side of the piston. The previous solution to this problem has been to drill or cast a second oil gallery at the hot side of the engine block at relatively great expense. Other solutions illustrate convoluted tubing that extends from the oil gallery.
What is needed is an expeditiously constructed cooling oil jet nozzle that remains aligned to spray oil at the intended piston area. What is further needed is an oil jet piston cooling system that is expeditiously fashioned to cool the hot side of a piston with an oil jet nozzle when the oil galley is on the other side from the hot side.